1. Field of the Invention
The present invention relates to a bit retention system and more particularly to an apparatus designed to retain and retrieve the head of a hammer/percussion bit in the event of separation or breakage of the head from the upper shank portion of the bit.
2. Brief Description of Prior Art
Percussion Hammer bit systems are commonly used in drilling or boring through the earth's surface. During application, it is known for the bit to fail and crack or break across the shank of the bit during drilling. Such failures often lead to “fishing” jobs which use expensive techniques to retrieve the broken bit from the well bore. In fact, most hammer bits in the art now include a fishing thread formed into the head of the bit to facilitate retrieving a broken head from a drilled hole. However, even bits having this fishing thread feature still results in a fishing operation to retrieve the broken bit head resulting in added expense to the operation.
The prior art is well supplied with variations and designs in order to retain the bit head to the hammer in the event of cracking and breakage. While each of the prior art systems may be unique in design, none of these provide the features of the current invention.
Thus there is a need for a system for retaining and retrieving broken percussion hammer drill bits. Further, it is advantageous for such a system (1) continue to retain a connection to the broken piece, (2) have a means for resisting disconnecting, and (3) protect the assembly as it is removed from the drill hole. The present retaining system meets these objectives.